Anti-backflow water control and solution proportioner

ABSTRACT

A plurality of ventable chambers in tandem with a valve between them and disposed between a source of pressurized municipal water and a flow-control solution-proportioning device. The chambers have movable walls that close vents and open backflow check valves under conventional water pressures, and then open the vents and close the check valves while positive gauge pressure still exists in the water supply but which has dropped to a predetermined low positive gauge pressure or to a pressure inadequate to operate the proportioning device successfully. Resilient means are provided to control the wall movements and the venting and to predetermine the desired positive gauge pressure differential across the vents at which the respective openings and closings will occur.

United States Patent 1 91 Hechler, IV

[ ANTl-BACKFLOW WATER CONTROL AND SOLUTION PROPORTIONER [76] Inventor: Valentine Hechler, W. 26 Meadow View Rd.. Northfield. HI. 60093" [22] Filed: Nov. 26, 1973 [2i] Appl. No.: 418,899

Related U.S. Application Data [63] Continuation-impart of Ser. No. 333,309. Feb. l6,

I973, abandoned. A

[52] U.S. Cl. 137/1, l37/6l4,2

511 1111. c1. Fl6k 11/00 58 Field ofSearch ..239/310, 311,313,335,

[56] References Cited- UNlTED STATES PATENTS 3,207,444 4 9/1965 Kelleyet al.., ..239/3l8 1 11 3,862,640 1451 Jan. 28, 1975 Primary Examiner-Henry T. Klinksiek Attorney, Agent, or FirmHarbaugh and Thomas 571 ABSTRACT A plurality of ventable chambers in tandem with a valve between them and disposed between a source of pressurized municipal water and a flow-control -'solution-proportioning device. The chambers have movable walls that close vents and open backl'low check valves under conventional water pressures, and then open the vents and'close the check valves while positive gauge pressure still exists in the water supply but which has dropped to a predetermined low positive gauge pressure or to a pressure inadequate to operate the proportioning device successfully. Resilient means are provided to control the wall movements and the venting and to predetermine the desired positive gauge pressure differential across the vents at which the respective openings-and closings will occur.

A 32 Claims, 13 Drawing Figures 1 j ANT I-BACKFLOW WATER CONTROL AND SOLUTION PROPORTIONER CROSS REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part of Hechler application Ser. No. 333,309 filed Feb. 16, 1973, now abandoned.

BACKGROUND OF THE INVENTION In the codes of an increasing number of states, for safety and ecological reasons, so-called anti-backsiphoning devices are required to be installed at a valve outlet of a potable water system if the level of the valved outlet from which the water flows is not above a potential flood level. This code requirement in a few states generally operates to protect the rest of the states on nationally merchandised products. Where valves are to be used with solutions, the test generally employed for acceptable performance against contamination involves placing wires in all check valves whichare in the path of reverse flow if there is no acceptable vacuum breaker," per se, in the pure water line ahead of the valve outlet. The wires are either 0.040 inch or 0.050 inch in diameter as related to the size of outlet openings. Very few valve devices, if any, have passed this test where a conduit-or nozzle extends beyond a proportioning device.

Although a wide variety of chemicals can be diluted and sprayed by an aspirating sprayer having a greater than minimum air gap and can be used as located at the outlet end of a hose, the physical burden and inconvenience of hand carrying the chemical concentrate supply for a large area, the difficulty of directing the spray in upward directions and intermittently valving the dispensing have been deterrents to proportioning bulk chemicals in a water solution utilizing municipal water pressure. A large tank of preproportional liquid solution that is independently pumped or pressurized is even a greater burden, and the use of a spreader for dry chemicals followed by wetting with a water spray is a time consuming dusty task.

It will be appreciated that proportioning devices theoretically can be located at either end of a garden hose, but, the location of the intermittently operated manual flow control valve becomes a critical consideration. The location of the proportioner at the water outlet valve ahead of a garden hose attached to it has not heretofore been properly protected with anti-siphon devices because if an intermittently operated shut-off valve is at the outlet end of the hose, the shut-offs from time to time trap water under high pressure in the hose and present a contamination problem due to the pressure-volume resiliency of the hose downstream of the proportioner. The radial stretch of the wall of the hose provides a volume of solution that can be forced back under pressure and varies as the square of its change of radius. Even with a conventional fixed minimum safety gap provided to prevent contamination by a backflow having a closed sprayer valve at the discharger end,'the potential backflow could be approximately one-half gallon in a ISO-foot hose when subjected to 70 p.s.i.g. Otherwise, the sprayer has to be open at all times even if there is a vent valve present that would open under negative water pressure. However, in both instances the backflow and water supply could continue to run wastefully between spray applications, and in all cases,

- ing device, because a mixture that is made beyond the control valve may find its way back into pure water supply under vacuum conditions or faulty backflow check valves involved during closings. The biggest danger is faulty check valves and delay in closing, and, this is tested by faulting" the check valve with the use of the testwires mentioned under simulated water flow and pressure conditions that are most adverse. Then if one millionth part of test solution reaches the potable water supply when backflow vacuum is applied to the device, the device is rejected.

SUMMARY OF INVENTION The present invention is concerned primarily with a manual flow control and proportioner supplied with pressurized municipal'water as the terminal dispensing unit, with or without a hose,'upstream to it.

The significance of the invention will be more clearly understood as the summary and description proceed if the effect of the wire test mentioned for approval is kept in mind, as if all valves are faulted by 0.050 inch wire to represent the danger and the amount of the dangerous backflow leakage that might be encountered with leaky valves. Such also represents a novel forward flow operation with little, if any, waste of water or solution.

The work siphoning generally contemplates a vacuum-type or negative gauge pressure ranging O-l5 pounds per square inch absolute (p.s.i.a.) with relation to atmospheric pressure referred to as 15 p.s.i.a., or as,

0 pounds per square inch gauge (p.s.i.g.).

In the present invention the protection begins at a low pressure above atmospheric pressure and can be as high at 10 p.s.i.g., preferably not below 4 p.s.i.g., and, preferably at a gauge pressure which may be too low for acceptable operation of the proportioning device. Thereby, the mixingdevice can be connected to the municipal water supply system and safely operated and also carry a dispensing wand or nozzle at its outlet for multi-direction discharge. The manual flow control valve can be located ahead of the proportioning device rather than at the outlet thereof. Furthermore, the device can be used in any gaseous environment at any pressure where the water pressure is supplied at a higher pressure. Thus p.s.i.g. refers to pressure over that of the external pressure environment of the device. Reference and incorporation herein is made of said Hechler application for a representative use of proportioning and application being made of the municipal water.

Two chambers are preferably provided that have movable side walls which when subjected to adequate water supply pressure coact with each other to close vent openings in their side walls. Movable end walls carry valve ports for automatic flow control valves preferably coordinated for predetermined coaction as resiliently closed at low p.s.i.g. water supply pressures.

. Lost motion means is disposed between the movable whereby there is no leakagewhen any positive working pressures are applied. Furthermore, the downstream chamber is minimal; in volume and is greatly enlarged when vented and drained while water pressure still exists in the upstream chamber. Then the downstream valve is closed and the upstream chamber vented and the downstream backflow check valve is positively closed while the port between the two chambers is closed positively by the flow controlvalve as the upstream chamber is washed with fresh water still under pressure after the venting has begun.

One ofthe objects is to provide a vent valving construction whose opening dimension is wide enough that surface tension is eliminated for emptying chambers and a flexible rolling sleeve seal of minimum friction is so supported that a pressure differential across it will not injure it'by extrusion'through the otherwise wide vent opening in the housing.

Another object is to provide a structure and arrangement having a flow capacity of as much as 7- I2 g.p.m., with 20 to I p.s.i.g. water supply pressure which under normal conditions will not permit any propor-' tional water mixture to' contaminate the fresh water supply upstream of the intermediate valve and will so perform while there still is positive pressure on the supwalls to assist coaction therebetween for coordination significant progressive positions of the parts as'opening steps of the device under water pressure and the inverse order of FIGS. 6, 5, 4, 3, in that order. illustrates the significant closing steps provided for safeguarding 'the municipal water system while'there is still a gauge pressure being applied through the hose connected to the device.

Accordingly, the representative device is illustrated by way of example as a manually controlled proportioner-mixer-dispenser gun 9 connected to the outlet of a garden hose '17 to utilize municipal water as a source under a normal working pressure ranging from to I00 p.s.i.g. The gunis constructed to safeguard against below contamination of the water source by any solution remaining undispensed in event the water pressure drops towardszero gauge pressure and before it drops that low. The anti-.backflow control is initially activated at 6 to l0.p.s.i.g. as determined by a selfacting resilient means and the device is vented wide ply water. All flow chambersdownstream thereof are vented to atmosphere and emptied ofany water that may have been therein. I

; IN THE DRAWINGS.

FIG. 1 is a perspective view of a preferred embodiment of the invention as manipulated in use and operation;

FIG. 2 is a'longitudinal sectional view through the gun-handle portion of the equipment shown in FIG. 1;

open to atmosphere when the pressure drops below approximately 4 p.s.i.g. well before vacuum is effective at the inlet of the device. Thus, until zero p.s.i.g. is reached, backflow is prevented by forward pressure flow of fresh water and the device is fully vented by the time zero p.s.i.g.. is reached. Moreover, while the pressure is between -4 and 6 p.s.i.g., the chambers are flushed with fresh water, and above 6 p.s.i.g.,the de: vice attains and, maintains its ready-to-operate condition during both a constant and an intermittent dispensing as controlled by the manual flow control valve.

Referring now to FIGS. 1 and 2, a unitary housing 10 is molded of a plastic such as polypropylene or acetal resin, dependinguponpressures-.handled such as mu- FIG. 3 is an enlargement of the 'valve portion of the sectional view of FIG. 2 with the valves and chamber defining elements in their normally full venting positions with no water pressure applied;

FIG. 4 is a view similar to FIG. 3 showing the first significantposition of the members during the time water pressure is being applied above a selected critical gauge pressure;

FIG. 5 is a view similar to FIGS. 3 and 4 illustrating the next significant position of the members as the water pressure exceeds the critical gauge pressure;

FIG. 6 is a view similar to FIGS. 3, 4 and 5 illustrating the members in their. working positions, fully pressurized and ready for operation;

FIG. 7 is a view similar to FIG. 6 illustrating the initial dispensing step with only the pilot flowcontrol valve open for limited flow;

FIG. 8 is a view similar to FIG. 7 illustrating the pilot and main flow control valves open for full flow;

FIGS. 8A, 8B and 8C are sectional views taken on these respective lines in FIG. 8.

FIG. 9 is a longitudinal sectional view similar to FIG. 7 illustrating another embodiment of the invention op- DESCRIPTION OF A PREFERRED EMBODIMEN The order ofFIGS. a, 4, 5,6, 7 and 8 illustrates the er'ational through the same sequences illustrated in nicipal water pressure. The housing has an elongated compartment 11 therethrough with internally cylindrical walls for ease of assembly without need for relative rotational adjustments. Its inlet end opening 12 receives a hose adapter 13 that is held in .place by pins 15 to provide a coarsely threaded opening 14 (FIG. 3) for receiving only an outlet male fitting 16 that is conventionally provided on a garden hose 17. The end 18 of the fitting l6 seals against a washer 20 supported by a shoulder 22 and has'embedded therein the marginal edge flange 19 ofa spherical screen member 21. An external groove 25 is provided on the adapter.

The outlet end 26 of the housing is externally threaded with an unconventional thread 28 or a castellated keying system, or both, which prevents standard water hose connections of gardening equipment being reversely or improperly made. Only an intended unique outlet fitting such as a conventional nozzle 30 can be attached'that preferably is open continuously for discharge to atmosphere at at 31.. Intermediate the inlet and outlet and proximate to the inlet opening the housing wall is provided with larger longitudinal vent openings 29 bordered by reinforcement ribs 33 extending from a circular flange 37A internally defining a surface of revolution to guide reciprocating parts therein and an intermediate flange 37. i

The adapter 13 internally defines spider-type openings 32 and supports a mandrel 34 having a valve head 35 defining a circumferential groove receiving aseal such as an O-ring or a washer externally tapering forwardly.

Coacting with the valve head 35 is a valve member which may be referred to as a snorkel 38 which slides substantially frictionlessly in guided relation upon the 5 inner edges of the ribs 33 and flange 37A on the housing wall as located upstream of the elongated vent openings 29 where a space 31 is provided between the snorkel and housing wall. Interconnecting the downstream edge 39 of the snorkel 38 and the groove 25 on the adapter is a resilient telescoping rolling sleeve seal 40 having thick anchor rings 41 and 42 supporting an intermediate web portion 43 in said space 31 to frictionlessly seal the upstream side of the snorkel from the vent openings 29. The rolling seal 40 is never subjected to more than 10 p.s.i.g. but what its bight portion preferably being supported by the flange 37.

Internally of the snorkel 38 a water passage 44 is defined receiving in its lower end of the valve head 35 with the ring seal 36 therein where an entrance section 45 of the passage 44 is 0.0linch to 0.015 inch larger in diameter than the seal 36 to provide a restricted flow passage 46 (FIG. 4) between the wall and the valve head. This provides a water jetting action until the seal.

36 acting as a valve reaches and passes a shoulder 47 at the entrance to a section 48 of the passage that is reduced in diameter to coact as a cylindrical valve seat with the seal 36 (FIG. in a preferably sliding or rolling lost motion relationship. Beyond the upper limit of the relative head 35 movement the passage narrows to a throat 50 which can be of a selected size to determine the flow capacity of the device, if desired, and marginally outward therefrom the snorkel 38 is shouldered at 51 to receive a ring seal 52 fitted thereon as held'in place by spring 59.

Downstream from the snorkel 38 is disposed a sleevetype multiple valve member 54 defining a shoulder 55 for one valve element and reciprocably mounted in-the housing as slidably guided by an external flange 56 with the upstream end edge 57 coacting as a valve seat with the snorkel seal52 to serve as a vent valve 58. The spring 59 between the seal 52 and flange 56 urges separation of the elements of the vent valve 58 described. The third valve is the main valve.

Downstream of the sleeve valve member 54 the housing 10 is reduced in diameter to provide a shoulder 72 facing upstream against which a valve member partition 74, defining a flat valve seat 73 that is engaged by the shoulder 55, is squared by the conical taper 77 and cone 79 therein resting at the downstream end of the vents 29. The partition 74 is held in place by a compression spring 76 interconnecting it and the downtionship and the pilot valve 66 coacts with an internal cylindrical wall seat 82 in the head of the main valve 68.

The valves are constructed and arranged as follows for a lost motion between the control valve assembly 64 and the sleeve valve 54 for a take-up between the valve assembly and the sleeve valve 54 to operate a backflow check valve 84 downstream of the control valve assembly 64 along with the further function of the check valve to prevent activation of the manual control when the chambers are vented (FIG. 3). Then when the backflow check valve closes, a chamber 78 is established between it and the main valve 68 which is vented through the vent valve 75.

For this purpose the downstream side of the main valve body 68 is tapered at 86 upstream of the cylindrical main valve port 70 to engage the taper of the valve stop 62 for centering alignment and positive displacestream side of the flange 56 on the sleeve 54. The

spring 76 urges separation of the sleeve from its conical-guided valving contact with the partition member to act as a vent valve 75 and to provide an enlarging second chamber 78 (FIG. 5) vented through the vent opening 29 when the valve members separate.

Adjacent its downstream end the inner wall 60 of the sleeve valve member 54 defines an inwardly tapered frusto-conical valve stop 62 that spacewise centers and accommodates the control valve assembly 64 concentrically therewith in guided relation. The assembly 64 comprises a pilot valve 66 and a main valve 68 (FIG. 7) and the taper 62 ends in a cylindrical valve seat or port 70 (FIG. 8) for the main valve 68 and has a diameter slightly greater than the snorkel throat ahead of it. V-rings 66V and 68V are mounted to coact in sliding relation with respect to the ports of the pilot valve 66 and main valve 68. The main valve 68 coacts through an opening 80 in the intermediate partition 74 with the cylindrical port 70 on the sleeve when in closed relament thereby under action of the spring 76. The upstream margins of the pilot valve 66 overlap the main valve body 68 with. a disk portion 88 to displace the pilot valve stem 90 and removeit from possible engagement with the manual actuator 92 when the device is fully vented FIG. 3) and the check valve closed against the partition member 74. Thereby, the valve also moves as a part of the sleeve 54 duringventing to obstruct backflow intothe chamber 49 defined by the sleeve member 54.

Either one of the two interengaging faces of the pilot and main valves is corrugated as at 92 (FIG. SC) to permit a balance of water pressure on opposite sides of the pilot valve disk portion 88 overpredetermined equal areas which preferably constitute the differential area between the effective valve areas of the main and pilot valves. Also, the taper of the main valve is corrugated for a like purpose as at 93 (FIG. 6). This provides for ease in manually opening the pilot valve to equalize pressure areas on opposite sides of the main valve for opening it. See Hechler US. Pat. No. 3,709,259.

The pilot valve 66 preferably is an integrated part of a stem assembly 90 having radial vanes 96 providing water flow spaces between them with their peripheral edges radially reduced upstream as at 97 for mutual concentric lost motion guidance with the main valve body 68 and for guidance in the cylindrical main valve port 70 over the remainder of their length.

The check valve 84 comprises a cage 100 (FIG. 8A) carried by the stem 90 downstream of a valve disk 102 at the end of the vanes and includes a resilient washer 104 on the upstream side of the disk 102 closing against the partition 74, thereby acting through the main valve and the pilot valve to limit the venting movement of the sleeve valve 54 so that the snorkel can move farther and break contact therewith for opening the vent valve Flow past the check valve 84 downstream thereof, when open, is provided around the disk 88 and radially between legs 105 having cross rods 106 on their ends engaging one end of a coiled compression spring 107 that is supported at its other end by the partition 55 to urge the opening of the check valve. Referring to FIG. 9, the check valve 84 is modified to be self-closing and the manual controlled valve assembly is rearranged so that the interengaging elements that permit the coaction of the main valve 68 and the pilot valve 64 may be performed by cooperating elements that are disposed upstream of the assembly 64.

The peripheral margin of the main valve 68A is provided with integrally molded bosses 92A thatare diametrically opposite and have guide arms 92B extending axially upstream. The arms are longitudinally slotted at 92C so that the remote end thereof serves as a stop 61A to engage the pilot valve to limit the lost motion extension between the valves.

, Diametrically opposed pairs of ribs extending longitudinally on the internal wall of the sleeve valve mem ber 54A provide guide grooves engaging the outer sides of the guide arms 92B and diametrically spaced radial projecting tabs 63 on the edge-of the pilot valve disk 66A engage in guided relation in the inner portions of the slots 92C as related to two recesses 91C in the upstream tapered wall portion which are provided to accommodate the base of the arms 923. The relationship is particularly shown in FIG. 3 where the upstream taper conducts to the side wall of the sleeve any liquid that may flow back through or off of the upstream faces of the valves. The lost motion provided permits the pilot valve to open first and then the tabs 63 of the pilot valve 66 engage the end stop 61A and, with further movement of the pilot valve 66, the main valve is opened.

The check valve 84 already described is divided in this embodiment into two parts: 1) the disk 84A which slides upon the stem 108A to close the valve seat 70 at all times when there is no pressure flow therethrough; and 2) the cage 100A which supports the one end of the spring 107A to urge closure .of the valve assembly while the effort of the other end is directed centrally to the check valve 84A a reduced diameter end turn of the spring 107A. Thereby, vanes 96 are not required to guide the stem 108A, the flow remaining at least the same while the backflow check valve is a normally closed one to inhibit backflow immediately, if any occurs.

The inner end 108 of the stem 90 extends in an axial direction through an opening 109 ina cross-wall portion 110 having a cup-molded shape 11] carrying a V- ring seal 112 therein which seals the stem as terminally exposed to atmosphere in a housing recess 113.

in making up the assembly of the elements described,

the check valve seal 104 is mounted in place on the check valve disk portion 88; the spring 107 is slipped into place and the partition 74 slipped over the vanes 96. The sleeve valve element 54 is then moved into place with the spring 76 collapsed .between the flange 56 and the partition 74. Thereupon the main valve member 68 and the pilot valve 66 are assembled on the stem 90 with their V-rings 66V and 68V in grooves provided for them and the pilot valve disk 88 may be suitably secured in place. In the embodiment shown the stem 90 and the disk 88 are threaded tightly together as made up preferably when the disk is still warm from its welding operation and the stern cooled for a tight fit when the temperatures equalize. Another way would I be to place the disk in position and then liquid weld it,

or distort it by mechanical blows or heat displacement of the thermoplastic. Either securement would be quite adequate because the maximum separation load exerted on the securement is the combined effort of the springs 107 and 76 under vented-conditions (FIG. 3) when the effort of the spring 76 is lessened by substantial expansion and the counter effort of spring 59. Otherwise, the greater forces of the water pressure are in the direction of maintaining the securement. Thereafter, the V-ring 112 is slipped over the valve stem and the assembly is moved into the position indicated in FIG. 6. Following that, the spring 59 is slipped into place awaiting the subassembly of snorkel 38.

The snorkel 38 has the downstream edge 41 of the rolling sleeve seal 40 pressed into place; the ring seal 36 is placed on the mandrel 34 of the adapter 13'. and, the upstream anchor ring 42 of the seal 40 is slipped into place. This subassembly is pressed into place and the pins 15 inserted and pressed tight to secure the assembly in the locations shown in FIG. 3. The gasket washer 20 carrying the screen 21 is pressed into the adapter and the device is ready for connection to a garden hose 17. Removal of the pins 15 permits easy servicing if ever required.

As more particularly disclosed and described in Hechler Ser. No. 333,309, for manual actuation of the flow control valve assembly, a longitudinal channel 124 (FIG. 8B) is formed in the wall of the housing 10. A lateral opening 121 narrowed by convergingly tapered walls 127 laterally receives a push rod 126 that is pressed in a radial direction and snapped into assembled longitudinal sliding supported relation with an L- shaped end 128 thereof reciprocably received in the recess 113 that is molded for that purpose ahead of the wall to engage and manually actuate the valve stem 108 when it projects into the recess.

The "front end of the push rod 126 (FIG. 2) is reversely formed to provide a thumb handle 132 which transmits valve actuating pressure in a direction also holding the rod 126 in the channel 124. A full flowpassage 136 from the flow control and check valves is the U-shaped, passage 136 around the recess 113 leading to the forward part 11F of the compartment. The forward compartment removably receives jet pumps 131 and 133 operating in tandem within a unitizing shell 134 for ready replacement for different chemicals and proportions as terminally sealed by flat rings 135 and 137 and held in place by a collar 136 received on the thread 28 on the housing 10 to hold the nozzle 30 at the outlet end 26.

The jet pump system preferably is a two-stage one in each of which converging walls 140A and 140B leading to jet nozzles 142A and 1428 convert pressure on the water to jet-flow energy and the jet is directed through openings 144A and 144B into mixing chambers 146A and 1468 having a flow area larger than the nozzle where water molecules transfer energy to and entrain molecules of the concentrate and then flow through second coaxial openings 148A and 148B respectively in relation to the differential in sizes of the openings 144 and 148 to provide a predetermined proportioning ratio. Thereupon the mixture passes through expanding walls 150A and 150B respectively to convert the flow energy back to pressure for ejection through the dispensing nozzle 30 having a flow area substantially less than the water flow area ahead of the jet pump when the water is above a predetermined low pressure. A compartment 138 receives the concentrate and this is supplied to the first mixing chamber 146A. In a twostage pump the mixture output of the first stage expanding walls 150A preferably is supplied as the concentrate to the second mixing chamber 1468. The ejection nozzle can be removed and also the second diverging wall 150B that converts to pressure if an ultimate soft flow is desired.

The concentrate supply 160 is in a bottle 162 that is open to atmosphere as carried by a strap 164 depending from a stud 166. A dip tube 168, including a hose connection 169, extends from the bottom of the container to a nipple 170 leading to the compartment 138 that is in communication with the gap of the first pump and preferably has a backflow ball check valve 169 in it to maintain the concentrate prime in the system as well as prevent dilution when the check valve 84 is closed. A tab 171 is provided upon which a manual valve (not shown) may be mounted intermediate the hose 169 and nipple 170.

It will be noted that the housing serves as a combination carrying handle and directing gun, and if it is pointed above the horizon, mixture will remain in the pump compartment capable of gravity flow back into the pure water that is ahead of the backflow check valve 84 if the pressure there drops below gauge pressure. This is to be inhibited; and, if any does pass through a faulty check valve, it must be prevented from reaching the fresh water ahead of the snorkel 38.

Accordingly, in operation, all valves, including vent valves, are open, except the check valve 84 and inlet valve 38 (FIG. 3), when the device is secured to the outlet end of a spigot valve or by a hose connected to When an increasing pressure reaches a positive pressure, preferably 4 p.s.i.g. (FIG. 4), the effort of the spring 76 begins to overcome by the effect of water pressure upon the exposed movable area of the snorkel 38 and it begins to advance towards the valve sleeve member 54 until the seat 47 thereof radially clears the ring seal 36. Thereupon, with continuing movement a further predetermined distance, there is an approximate 0.005 inch clearance remaining to permit water to jet through and against the face of the pilot valve 66 and wash the interior of the valve sleeve member 54 before the mandrel 34 andvalve cylinder 38 completely close (FIG. 5) the vent valve 58.

Upon closure of the vent valve 58 pressure additionally begins to build up below the pilot valve 66, and at 6 p.s.i.g., the snorkel 38 and valve sleeve member 54 are moved upwardly against'the spring 76 whereupon the inlet valve mandrel 34 opens to a full flow and the valve sleeve member 54 closes against the partition (FIG. 6) to close the vent valve 75.-The main valve assembly stem 108 moves the push rod 126 to its ready position for thumb operation. Thereby, the device is pressurized ready for operation. In this relation the device can serve as a lawn sprinkler or washdown device with or without any concentrate supply being furnished to it.

Thereafter, with a concentrate supply 160 connected ready to perform, the pilot valve 66 can be actuated (FIG. 7) and water, under a pressure higher than 6 p.s.i.g., will activate the proportioningand mixing of water and concentrate in the jet pumps as described. A preferable pressure for accurate proportioning, however, is above 10 p.s.i.g., it being appreciated that tensions on springs 59 and 76 can be provided to accomplish any opening pressure desired, the frictional factors being quite low in the device for reasons described.

Manually opening the pilot valve first, even against l00 p.s.i.g., encounters only an effective pressure differential area requiring a lineal force less than 4 lbs.

' and permits a balancing of pressure on opposite sides of the main valve 68 when open. Thereupon, the main valve can be opened with easy thumb pressure for a 0.5 inch diameter flow opening to provide a 7.5 gals-perminute flow. The device then remains in pressurized and ready condition throughout continued or inter mittent operation and no contaminating backflow of mixture will occur.

If the water supply pressure begins to drop, whether the flow control valve 64 is open or closed, the ultimate results will be approximately the same. In both instances there will be no pressure above the flow control valve 64 since downstream it is open to atmosphere at the nozzle. Therefore, the spring 76 will urge the valve sleeve 54 to break sealing conctact with the partition 55, thereby increasing the space between the manual valve 64 and check valve 84 and vent the chamber 78 thus created to atmosphere through the opened vent valve downstream of the main valve (FIG. 5). The spring 76 will further move the valve member 54 and thereby the snorkel 38 into close proximity to the mandrel 34, and as the pressure lowers to 4 p.s.i.g., the mandrel-snorkel inlet valve 38 begins to close permitting water to continue to move .under pressure through the 0.005 inch clearance 46 provided therebetween to wash the upstream chamber as the snorkel-sleeve vent valve 58 begins to open. Water will continue to flow therethrough to atmospheric pressure until the snorkelmandrel inlet valve 38 closes. Thereupon, the chamber defined by the snorkel-sleeve valve elements is also completely vented and drained.

The moving parts are small and light for a 7.5 gals.- per-minute (g.p.m.) flow and therefore are fast moving. It is extremely doubtful that a vacuum condition occurring at the mandrel operates fast enough to apply a vacuum to the mandrel-snorkel inlet valve 38 before it is closed. Even if this valve is faulted, the venting of the snorkel-sleeve chamber through vent valve 58 would prevent vacuum being applied to any other valves downstream thereof, particularly with a chamber 78 beyond the control valves, vented first through vent valve 75 even if the flow control valves were faulted, it being impossible to hold them open manually without the venting occurring first.

Furthermore, if there is any column of mixture above the backflow check valve 84 and it is faulted, any flow passing the partition opening 104 would flow divergingly on the conical surface on the valve stop 62 to the vent opening 75. This would be true also a the main valve if it were faulted, there additionally being nothing but atmospheric pressure above it. Any seeping would flow down the guide wall 60 outside the area presented by the snorkel opening and woud flow out vent 58 even if the device were held vertically erect.

Thus, venting is immediately large and the chambers vented have had very little water in them to start with. The upstream chamber is snorkel-washed both when venting and pressurizing and the other chamber downstream is minuscule to start with. All valves are positively closed, except the vent valves, during venting.

Thus, with the venting and backflow check valves completing operation positively while there still is positive gauge inlet pressure, the venting of at least one chamber protected at its inlet and outlet by backflow check valves prevents vacuum conditions that might exist for the inlet backflow check valve from becoming effective upon the outlet backflow check valve. Thereby, there is no pressure across the outlet backflow check valve, particularly if there has also been a venting downstream therefrom. Furthermore, if the chamber is minuscule in size during operation and is rapidly and greatly expanded while being vented, there is little, if any, opportunity for leakage back through the inlet backflow check valve. Assuredly, this is true if there is a slow closing because of fresh water from the inlet flow through it under pressure, irrespective of which member of the valve is the one that is moving.

Furthermore, with the manual flow control valve also serving as a backflow check valve between two chambers, a great economy of space and water volume and weight is attained in safeguarding the fresh water supply from contamination.

A plastic particularly adapted for the purposes herein set forth is an acetal homopolymer sold as Celcon (a proprietary name of Celanese Plastics Co.), or acetal copolymer sold as Delrin (a proprietary name of Du Pont), both of which are thermally stable over a wide range of stresses, temperatures, and environments for easy molding in unusually short cycles with negligible change in dimensional characteristics.

What is claimed is:

1. An anti-contamination device for a pressurized potable water system having a dispensing outlet;

a housing defining a compartment having an inlet means connectable to said dispensing outlet, an

outlet means connectable to a dispensing means.

and vent means disposed between the inlet means and outlet means;

a normally closed inlet valve in communication with the inlet means and including a first member moved by water pressure at the inlet means to open the inlet valve;

an outlet valve in communication with the outlet means closing in the direction of flow of water to the outlet means and including a second movable member;

resilient means for urging the second member to connect said outlet means in communication with said vent means;

said members defining a chamber between said valves; and

resilient means urging separation of said members to vent said chamber when the water pressure at the inlet is a low predetermined positive gauge pressure.

- 2. The device defined in claim 1 in which said outlet means includes:

a backflow check valve and including:

a partition defining a chamber means between said second movable member and said backflow check valve.

3. The device defined in claim 1 in which said inlet valve means includes a mandrel and sleeve valve movable with respect to each other with a lost motion between and a jet clearance between them over a portion of theirrelative movement.

4. The device defined in claim 1 in which the two members have openings at their downstream ends with walls diverging therefrom in the upstream direction to said vent means.

5. The device defined in claim 1 in which resilient sleeve means interconnects one of said members and the housing disposed folded back upon itself in a space between the housing and said first member;

means for securing one of the ends of the sleeve to the housing; and

means for securing the other end to the first member with the bight between the folds subjected to said pressure.

6. In a fluid flow control device the combination of a housing member defining a space;

conduit member supported in said space with its sides spaced from the housing to define a space therebetween;

resilient sleeve means disposed in said space fastened at one end to one of the members and folded back upon itself and fastened at its other end to the other member to provide a rolling sealat the bight between the members, said space being at least twice the thickness of the wall of the sleeve means.

7. The fluid flow control 'device defined in claim 6 in which the wall of said sleeve is exposed to pressure on one side, and said sleeve has its ends thickened on the other side of the wall; 7

said members having recesses facing towards said spaces receiving said thickened ends with the pressure between said members being directed into the bight of said fold.

8. The device defined in claim 6 in which one of said members has a guide flange intermediate said members external of said bight supporting said bight against pressure at one end of the relative movement of said members; and Y mechanical means for returning said members to the other end of their relative movement.

9. The device defined in claim 6 in which said members are extended by said pressure in their relative movement and the length of said sleeve unfolded is greater than the distance of said relative movement between the members.

10. The device in claim 6 in which the fluid pressure moves the members in one direction; and including mechanical means moving the members with respect to each other in the other direction.

11. An anti-contamination device for a pressurized potable water system having a dispensing outlet;

.housing means defining a compartment having an inlet for connection to said dispensing outlet, an

outlet means and a vent mea'ns disposed between said inlet and outlet means;

a normally closed inlet valve means in said compartment between said inlet and vent means including a valve member movable to open said inlet.valve means under incoming water pressure;

a normally open valve adjacent to the outlet means disposed between the vent and outlet means including a valve member movable by pressure to close said normally open valve;

said movable members defining a chamber;

valve means between said movable members opening to said vent means to vent said chamber; and

resilient means urging relative movement between I said movable members to open the valve means between them. 12. The device defined in claim ll in which one of said movable members has an outlet port; and includmanual flow control means coacting with said port to close it under pressure present in said chamber.

13. The device defined in claim 12 including a normally open backflow check valve carried by said flow control means to its closed position when said one of said movable valve members is moved to open said vent means between said movable members.

14. In an anti-contamination device for a pressurized potable water system having a dispensing outlet;

housing means defining a compartment having an inlet for connection to said dispensing outlet, an outlet means and a vent means disposed between said inlet and outlet means;

said compartment including a movable member opening said vent, and an inlet valve, both valves closing under pressure, said inlet valve comprising a check valve that is open under pressure; and

resilient means urging said chamber means to move said valve member to open to said vent;

said movable member in its movement closing the flow control valve and the check valve to vent the space between them.

15. A safety device for dispensing a solvent and protecting it against backflow contamination comprising:

a housing defining a compartment having an inlet, an

outlet and a vent;

an inlet valve means including a valve member reciprocably mounted to normally close the inlet and responsive to inlet pressure for opening the inlet;

an outlet valve means including a valve'member closing in the direction of backflow; and

two intermediate members reciprocably mounted in said compartment with respect to each other to join under liquid pressure at said inlet to form a chamber interconnecting said inlet and outlet; and

means urging said sleeve members to separate at a pressure differential between the liquid pressure at the inlet and the pressure at the vent.

16. The device defined in claim 15 in which said inlet valve includes a lost motion means for progressively opening the inlet valve means in sequence with the joining movement of the two intermediate members.

17. The device defined in claim 15 including check valve means at the outlet of said chamber closing in the direction of backflow of liquid to the chamber.

18. The device defined in claim 15 in which the end contours of the intermediate members taper in the downstream direction.

19. An anti-backflow protector for a municipal water system service outlet comprising:

housing means open to atmosphere having a vent opening intermediate an outlet and an inlet, said inlet being connectable to said service outlet;

a pair of conduits supported in tandem in the housing reciprocably with respect to each other in one position of which they are in sealed liquid conductive relationship between the inlet and outlet and in the other position of which they are parted and both are open to atmosphere adjacent the vent opening;

a flow check valve closing each of the conduits in their said other position; and

means responsive to a predetermined pressure at said outlet to close the flow check valve that is adjacent to said inlet and move said conduits to their parted position.

20. The protector defined in claim 19 including lost motion means interconnecting said inlet valve and said conduit adjacent to said inlet for closing said inlet valve to close the inlet adjacent conduit during the terminal portion of the parting movement of the conduits.

21. An anti-backflow valve construction comprising: a housing defining a compartment having an inlet connectable to a source of solvent under pressure. an outlet connectable to a dispensing means. and a vent to a basic pressure between them;

an inlet valveopening under inlet pressure including a valve member responsive to inlet pressure and urged to its closed position;

an outlet valve opening under inlet pressure including a valve member urged to its closed position;

' and vent valve means including valve member actuated to close above a predetermining low positive pressure upon theliquid disposed between said inlet and outlet valves.

22. The combination defined in claim 21 including a manual meansfor displacing and opening said outlet valve only when said vent valve means is closed.

23. The combination defined in claim 21 including a normally open backflow check valve disposed downstream of the outlet valve and means for closing said check valve when the outlet valve is closed when said vent is in communication with said manual valve.

24. The combination defined in claim 21 including means interconnectingsaid check valve and said manual valve for coexistent closing when said vent valve means is open. a

25. The combination defined in claim 21 in which said valve members having external end portions tapering in a downstream direction to diverge in the upstream direction towards said vent valve means and having valve sealing means bordering said divergence adjacent said vent;

said vent extending a major portion of the combined length ofsaid valve members.

26. The combination defined in claim 21 including main valve assembly comprising a large area circular disk having a small valve port through it and a pilot valve having a large area circular disk concentrically coacting to close said small valve port;

one of said disks having an irregular surface around said valve port on the side facing the other'disk, the ratio of the port area and the area of said irregular surface determining the effective area exposed to water pressure determining the amount of force required to open the small valve port.

27. The method of preventing contamination of a municipal water system dispensing water under pressure comprising conducting water under pressure to a point of mixing, diluting and mixing said water with a chemical and providing a mixture at said point, and venting the water proximate to and ahead of said mixing point to atmosphere at a predetermined low positive gauge pressure.

28. The method of preventing contamination of a municipal water system dispensing water under pressure comprising conducting water under pressure to a point of mixing, diluting and mixing said water with a chemical and providing a mixture at said point, and performing the combined steps of obstructing backflow from said point of mixing, obstructing reverse flow of water with respect to said conducted water and venting to atmosphere the water between said obstructions at a predetermined low positive gauge pressure.

29. The method defined in claim 27 including isolating said conduted water in plural bodies of water adjacent to the mixing point and venting both bodies of water to atmosphere.

30. ln a device of the class described the combination ofa housing defining a water chamber having a water inlet connectable to a pressurized potable water supply and an outlet;

a self-closing valve opening under outflow of water under pressure through said outlet;

a backflow check valve means for normally closing said inlet and opening said inlet in response to a predetermined rise in pressure differentials between the chamber and water supply pressure; and

means for venting the chamber directly to atmosphere when the pressure in the chamber drops to LII a predetermined low gauge pressure.

31. The device defined in claim 30 including a second chamber having an inlet, an outlet and means for venting the second chamber to atmosphere and in which said last mentioned inlet is the outlet of the first chamber and including a backflow check valve means normally closing the outlet of the second chamber;

said second chamber when vented isolating the first chamber for backflow pressure upon the outlet opening of the first chamber.

32. The device defined in claim 30 including a normally closed main flow control valve closing the outlet in the direction of water from the inlet flowing through the outlet. 

1. An anti-contamination device for a pressurized potable water system having a dispensing outlet; a housing defining a compartment having an inlet means connectable to said dispensing outlet, an outlet means connectable to a dispensing means and vent means disposed between the inlet means and outlet means; a normally closed inlet valve in communication with the inlet means and including a first member moved by water pressure at the inlet means to open the inlet valve; an outlet valve in communication with the outlet means closing in the direction of flow of water to the outlet means and including a second movable member; resilient means for urging the second member to connect said outlet means in communication with said vent means; said members defining a chamber between said valves; and resilient means urging separation of said members to vent said chamber when the water pressure at the inlet is a low predetermined positive gauge pressure.
 2. The device defined in claim 1 in which said outlet means includes: a backflow check valve and including: a partition defining a chamber means between said second movable member and said backflow check valve.
 3. The device defined in claim 1 in which said inlet valve means includes a mandrel and sleeve valve movable with respect to each other with a lost motion between and a jet clearance between them over a portion of their relative movement.
 4. The device defined in claim 1 in which the two members have openings at their downstream ends with walls diverging therefrom in the upstream direction to said vent means.
 5. The device defined in claim 1 in which resilient sleeve means interconnects one of said members and the housing disposed folded back upon itself in a space between the housing and said first member; means for securing one of the ends of the sleeve to the housing; and means for securing the other end to the first member with the bight between the folds subjected to said pressure.
 6. In a fluid flow control device the combination of a housing member defining a space; conduit member supported in said space with its sides spaced from the housing to define a space therebetween; resilient sleeve means disposed in said space fastened at one end to one of the members and folded back upon itself and fastened at its other end to the other member to provide a rolling seal at the bight between the members, said space being at least twice the thickness of the wall of the sleeve means.
 7. The fluid flow control device defined in claim 6 in which the wall of said sleeve is exposed to pressure on one side, and said sleeve has its ends thickened on the other side of the wall; said members having recesses facing towards said spaces receiving said thickened ends with the pressure betwEen said members being directed into the bight of said fold.
 8. The device defined in claim 6 in which one of said members has a guide flange intermediate said members external of said bight supporting said bight against pressure at one end of the relative movement of said members; and mechanical means for returning said members to the other end of their relative movement.
 9. The device defined in claim 6 in which said members are extended by said pressure in their relative movement and the length of said sleeve unfolded is greater than the distance of said relative movement between the members.
 10. The device in claim 6 in which the fluid pressure moves the members in one direction; and including mechanical means moving the members with respect to each other in the other direction.
 11. An anti-contamination device for a pressurized potable water system having a dispensing outlet; housing means defining a compartment having an inlet for connection to said dispensing outlet, an outlet means and a vent means disposed between said inlet and outlet means; a normally closed inlet valve means in said compartment between said inlet and vent means including a valve member movable to open said inlet valve means under incoming water pressure; a normally open valve adjacent to the outlet means disposed between the vent and outlet means including a valve member movable by pressure to close said normally open valve; said movable members defining a chamber; valve means between said movable members opening to said vent means to vent said chamber; and resilient means urging relative movement between said movable members to open the valve means between them.
 12. The device defined in claim 11 in which one of said movable members has an outlet port; and including manual flow control means coacting with said port to close it under pressure present in said chamber.
 13. The device defined in claim 12 including a normally open backflow check valve carried by said flow control means to its closed position when said one of said movable valve members is moved to open said vent means between said movable members.
 14. In an anti-contamination device for a pressurized potable water system having a dispensing outlet; housing means defining a compartment having an inlet for connection to said dispensing outlet, an outlet means and a vent means disposed between said inlet and outlet means; said compartment including a movable member opening said vent, and an inlet valve, both valves closing under pressure, said inlet valve comprising a check valve that is open under pressure; and resilient means urging said chamber means to move said valve member to open to said vent; said movable member in its movement closing the flow control valve and the check valve to vent the space between them.
 15. A safety device for dispensing a solvent and protecting it against backflow contamination comprising: a housing defining a compartment having an inlet, an outlet and a vent; an inlet valve means including a valve member reciprocably mounted to normally close the inlet and responsive to inlet pressure for opening the inlet; an outlet valve means including a valve member closing in the direction of backflow; and two intermediate members reciprocably mounted in said compartment with respect to each other to join under liquid pressure at said inlet to form a chamber interconnecting said inlet and outlet; and means urging said sleeve members to separate at a pressure differential between the liquid pressure at the inlet and the pressure at the vent.
 16. The device defined in claim 15 in which said inlet valve includes a lost motion means for progressively opening the inlet valve means in sequence with the joining movement of the two intermediate members.
 17. The device defined in claim 15 including check valve means at the outlet of said chamber closing in the direction of backflow of liquid to the chamber.
 18. The device defined in claim 15 in which the end contours of the intermediate members taper in the downstream direction.
 19. An anti-backflow protector for a municipal water system service outlet comprising: housing means open to atmosphere having a vent opening intermediate an outlet and an inlet, said inlet being connectable to said service outlet; a pair of conduits supported in tandem in the housing reciprocably with respect to each other in one position of which they are in sealed liquid conductive relationship between the inlet and outlet and in the other position of which they are parted and both are open to atmosphere adjacent the vent opening; a flow check valve closing each of the conduits in their said other position; and means responsive to a predetermined pressure at said outlet to close the flow check valve that is adjacent to said inlet and move said conduits to their parted position.
 20. The protector defined in claim 19 including lost motion means interconnecting said inlet valve and said conduit adjacent to said inlet for closing said inlet valve to close the inlet adjacent conduit during the terminal portion of the parting movement of the conduits.
 21. An anti-backflow valve construction comprising: a housing defining a compartment having an inlet connectable to a source of solvent under pressure, an outlet connectable to a dispensing means, and a vent to a basic pressure between them; an inlet valve opening under inlet pressure including a valve member responsive to inlet pressure and urged to its closed position; an outlet valve opening under inlet pressure including a valve member urged to its closed position; and vent valve means including valve member actuated to close above a predetermining low positive pressure upon the liquid disposed between said inlet and outlet valves.
 22. The combination defined in claim 21 including a manual means for displacing and opening said outlet valve only when said vent valve means is closed.
 23. The combination defined in claim 21 including a normally open backflow check valve disposed downstream of the outlet valve and means for closing said check valve when the outlet valve is closed when said vent is in communication with said manual valve.
 24. The combination defined in claim 21 including means interconnecting said check valve and said manual valve for coexistent closing when said vent valve means is open.
 25. The combination defined in claim 21 in which said valve members having external end portions tapering in a downstream direction to diverge in the upstream direction towards said vent valve means and having valve sealing means bordering said divergence adjacent said vent; said vent extending a major portion of the combined length of said valve members.
 26. The combination defined in claim 21 including main valve assembly comprising a large area circular disk having a small valve port through it and a pilot valve having a large area circular disk concentrically coacting to close said small valve port; one of said disks having an irregular surface around said valve port on the side facing the other disk, the ratio of the port area and the area of said irregular surface determining the effective area exposed to water pressure determining the amount of force required to open the small valve port.
 27. The method of preventing contamination of a municipal water system dispensing water under pressure comprising conducting water under pressure to a point of mixing, diluting and mixing said water with a chemical and providing a mixture at said point, and venting the water proximate to and ahead of said mixing point to atmosphere at a predetermined low positive gauge pressure.
 28. The method of preventing contamination of a municipal water system dispensing water under pressure comprising conducting water under pressure to a point of mixing, diluting and mixing said water with a chemical and providing a mixture at said point, aNd performing the combined steps of obstructing backflow from said point of mixing, obstructing reverse flow of water with respect to said conducted water and venting to atmosphere the water between said obstructions at a predetermined low positive gauge pressure.
 29. The method defined in claim 27 including isolating said conduted water in plural bodies of water adjacent to the mixing point and venting both bodies of water to atmosphere.
 30. In a device of the class described the combination of a housing defining a water chamber having a water inlet connectable to a pressurized potable water supply and an outlet; a self-closing valve opening under outflow of water under pressure through said outlet; a backflow check valve means for normally closing said inlet and opening said inlet in response to a predetermined rise in pressure differentials between the chamber and water supply pressure; and means for venting the chamber directly to atmosphere when the pressure in the chamber drops to a predetermined low gauge pressure.
 31. The device defined in claim 30 including a second chamber having an inlet, an outlet and means for venting the second chamber to atmosphere and in which said last mentioned inlet is the outlet of the first chamber and including a backflow check valve means normally closing the outlet of the second chamber; said second chamber when vented isolating the first chamber for backflow pressure upon the outlet opening of the first chamber.
 32. The device defined in claim 30 including a normally closed main flow control valve closing the outlet in the direction of water from the inlet flowing through the outlet. 